Explanation of erroneous statements about SMAC and CRASH
Posted: Tue Apr 07, 2015 11:31 am
The following is from McHenry Software webpage:Explanation of erroneous statements about SMAC and CRASH:
- For additional information on SMAC, CRASH and other accident reconstruction and simulation programs please see Over 50 years of McHenry Highway Safety Publications and also our main website www.mchenrysoftware.com
- 1985:
- In SAE paper 850255, "Inaccuracies in the CRASH3 Program" by Woolley, Warner & Tagg there were fundamental Inaccuracies in the paper!
- Please see our letter response to the authors of SAE 860255
- In SAE paper 850255, "Inaccuracies in the CRASH3 Program" by Woolley, Warner & Tagg there were fundamental Inaccuracies in the paper!
- 1987:
- In February 1987 at the SAE CRASH3 workshop, a speaker stated that they had found a bug/error in the CRASH3 program Trajectory Analysis procedure related to the friction zones. I quickly rose and corrected/educated the speaker that they were wrong, this was NOT an error/bug! The Trajectory solution procedure of CRASH uses logic and code from SMAC and the line defining the friction zones has a built in 'mirror image' for simplification of logic.
- I followed this up with a March 4, 1987 Letter w/attachments
- In February 1987 at the SAE CRASH3 workshop, a speaker stated that they had found a bug/error in the CRASH3 program Trajectory Analysis procedure related to the friction zones. I quickly rose and corrected/educated the speaker that they were wrong, this was NOT an error/bug! The Trajectory solution procedure of CRASH uses logic and code from SMAC and the line defining the friction zones has a built in 'mirror image' for simplification of logic.
- 1987:
- In October 1987 at a CRASH coefficient protocol subgroup committee meeting at SAE a company announced that they had quickly created a commercial 'crush coefficient database' product.
- Here is the October 26, 1987 SAE Committee Correspondence created to reiterate important and essential points made during the meeting about the creation of Crush Coefficients for use with CRASH and other damage analysis programs.
- In October 1987 at a CRASH coefficient protocol subgroup committee meeting at SAE a company announced that they had quickly created a commercial 'crush coefficient database' product.
- 1990:
- Starting in the 1980s a lot of 'experts' in litigation matters were misrepresenting the accuracy of CRASH and SMAC, and some were testifying and publishing that CRASH was more accurate than SMAC? (for example see the post below about a 2003 book!) And that CRASH was a highly accurate program! We contacted NHTSA and asked that they send a clarification of the status of SMAC and CRASH.
- In a Jan 30, 1990 letter Frank Richardson, NHTSA, Chief Field Operations for NASS responded to our request for clarification.
- Which includes:
- "NASS is a program to collect data on a large sample of highway crashes ...
- "The PC version of CRASH that we use... We know it has its limitations (see Carl Nash's SAE Paper 870040, CRASH3: Current Status, 1987 and our August 1989 response to GM Docket 86-06) but it is simple, inexpensive and well suited to the experience and education level of people we can afford to have collecting NASS data."
- "We have always recognized that the SMAC computer program, which was developed for NHTSA in 1972, is more sophisticated and more accurate than the CRASH3 we are using but the relative expense and application complexity make it unsuitable for our purposes"
- Also note due to the overwhelming requests from litigation attorneys about CRASH, NHTSA went about with a 'Reformulation of CRASH' and also created WinSMASH which is ONLY available for NHTSA NASS teams (so no public distribution) to avoid further time consuming litigation related inquiries about CRASH.
- Starting in the 1980s a lot of 'experts' in litigation matters were misrepresenting the accuracy of CRASH and SMAC, and some were testifying and publishing that CRASH was more accurate than SMAC? (for example see the post below about a 2003 book!) And that CRASH was a highly accurate program! We contacted NHTSA and asked that they send a clarification of the status of SMAC and CRASH.
- 1997:
- For the 1997 SAE congress the McHenry's published 4 papers and dealt with 8 reviewers as a part of the peer review process. It was a pleasure to work with 7 of the 8 reviewers and we thank them for taking the time and effort to review and provide constructive comments on our papers.
One of the 8 reviewers made the review process an unreasonable and offensive experience.- Please read about our experiences with the 1997 SAE peer review process
- For the 1997 SAE congress the McHenry's published 4 papers and dealt with 8 reviewers as a part of the peer review process. It was a pleasure to work with 7 of the 8 reviewers and we thank them for taking the time and effort to review and provide constructive comments on our papers.
- 1998:
- For the 1998 SAE congress the AR session organizers and SAE allowed a misinformed author to publish a paper Crush Stiffness Coefficients, Restitution Constants, and a Revision of CRASH3 & SMAC, as a failed attempt to rehabilitate the many ignorant mistakes he made as a unreasonable and offensive peer reviewer of our 1997 SAE paper Effects of Restitution in the calculation of crush coefficients.
- An apology for the offensive situation with acknowledgement of the many errors should have been required by SAE from the author prior SAE allowing the author to publish any paper related to the topic. The 1998 paper is simply a CYA by the author
- Please see the January 1998 update and our February 1998 update to our log of experiences with the 1997 SAE peer review process
- For the 1998 SAE congress the AR session organizers and SAE allowed a misinformed author to publish a paper Crush Stiffness Coefficients, Restitution Constants, and a Revision of CRASH3 & SMAC, as a failed attempt to rehabilitate the many ignorant mistakes he made as a unreasonable and offensive peer reviewer of our 1997 SAE paper Effects of Restitution in the calculation of crush coefficients.
- 2001:
- A paper related to our research on restitution contained a tremendous number of errors and fundamental misstatements.The paper was SAE paper 2001-01-0502: "Stiffness Parameters for Vehicle Collision Analysis, An Update" by Nystrom
- 2003:
- A book published in 2003 and brought to our attention in 2004 or so, has a section entitled "Issues to Watch out For" (p 86) where the authors make critical, somewhat silly, comments on SMAC like:
- "to compute these mutual vehicle collision forces SMAC uses an algorithm even less scientific than CRASH3"??!!
The book is- Low-Speed Automobile Accidents: Accident Reconstruction and Occupant Kinematics, Dynamics and Biomechanics, Third Edition, from Lawyers & Judges Publishing. By Alan J. Watts Ph.D.
- Please see our documentation of some serious errors in the Watts book
- A book published in 2003 and brought to our attention in 2004 or so, has a section entitled "Issues to Watch out For" (p 86) where the authors make critical, somewhat silly, comments on SMAC like:
- 2007:
- In 2007 IPTM published a hack job paper which attempted to trash SMAC and CRASH.
The paper is- Energy, Momentum and the Chaos of Time and is no longer available from IPTM.
- In 2007 IPTM published a hack job paper which attempted to trash SMAC and CRASH.
- 2008:
- In 2008, AAAM published a paper Minor crashes and 'whiplash' in the United States authored by Bartsch AJ, Gilbertson LG, Prakash V, Morr DR, Wiechel JF which incorrectly mentions m-smac and m-crash with no basis in fact or research: